Clamping bands are typically utilized for clamping one end of a resilient gasket into an opening. For example, U.S. Pat. No. 4,387,900 assigned to the assignee of the present invention discloses a gasket intended for use in an opening in manhole bases and which is intended for in situ installation within the openings of manhole bases which have either been precast at the factory or cored either at the factory or at a job site. A clamping band is urged against the gasket, placing the gasket under compression to effect a fluid-tight seal between the gasket and the opening in the manhole base. The opposite end of the gasket forms a watertight seal with a pipe extending through the gasket. The clamping band described in U.S. Pat. No. 4,387,900 is a plastic band which is substantially precisely pre-sized preparatory to delivery at the job site and is provided with a small insert portion hingedly connected to one of the free ends of the clamping band. The clamping band is expanded by suitable expansion apparatus and the pivotal wedge is swingably moved into the gap between the two free ends of the clamping band. The expansion force is released whereby the clamping band and cooperating insert maintain the clamping band in the locked position.
One of the problems with clamping bands of the above design is that there is a difficulty in insertion of the insert member and further that the clamping bands are not capable of compensating for large differences in opening diameter due to loose manufacturing tolerances when forming manhole base openings either in the factory or in the field.
An improved clamping band described in pending application Ser. No. 778,690, filed Sept. 23, 1985 and assigned to the assignee of the present invention eliminates the hingedly mounted insert, enabling the free ends of the clamping band to be moved into engagement and butt together. Nevertheless, this improvement suffers from the same disadvantages recited hereinabove with regard to the clamping band described in U.S. Pat. No. 4,387,900. In addition, the improved clamping band necessitates expansion of the clamping band to a degree sufficient to move the free ends apart by an amount sufficient to enable the overlapping end to snap outwardly into the locked position.